N-benzothienylchloroacetamides as preemergent herbicides



United States Patent 3,495,967 N-BENZOTHIENYLCHLOROACETAMIDES AS PREEMERGENT HERBICIDES Patrick R. Driscoll, Fords, and Harold A. Kaufman,

Piscataway, N .J., assignors to Mobil Oil Corporation, a corporation of New York No Drawing. Filed Feb. 7, 1968, Ser. No. 703,567 Int. Cl. A01n 9/12, 9/14 US. CI. 7190 2 Claims ABSTRACT OF THE DISCLOSURE N-benzothienyl-2-chloroacetamide and ringand N-substituted derivatives thereof are new compounds that are herbicides, particularly as preemergent herbicides.

Field of the invention This invention is concerned with herbicides. It is more particularly concerned with a novel class of N-benzothienylchloroacetamide herbicides.

Background of the invention There have been proposed, as herbicides, N-naphthyl- 2-chloroacetamides having a tertiary (C -C alkyl substituent in the 2-position of the naphthyl ring. Insofar as is now known chloroacetamides of heterocyclic compounds, particularly of benzothiophene, have not been proposed.

Summary of the invention This invention provides N-benzothienyl-Z-chloroacetamides having the formula:

wherein R is selected from hydrogen, alkyl (C -C4), cycloalkyl (C -C and alkenyl (C -C X, Y, and Z are selected from hydrogen, alkyl (C -C cycloalkyl (C C aryl, haloaryl, cyano, halogen, carboxyl, thiocyano, alkoxy (C -C alkylthio (C -C and nitro; n is 0, 1, or 2; and in which NGCHzGl X, Y, and Z may be on any separate 2-7 positions of the ring. This invention also provides a method for controlling plant growth with said N-benzothienyl-Z-chloroacetamides.

Description of specific embodiments The aforedefined N-benzothienyl-2-chloroacetamides of this invention are prepared by usual methods of amide formation. Thus, aminobenzothiophene, ring-substituted derivatives, N-substituted, or both ringand N-substituted derivatives (i.e. an aminobenzothiophene reactant) can be reacted with chloroacetic acid anhydride with slight warming. The chloroacetamides can also be prepared by reacting the aminobenzothiophene reactant with chloroacetyl chloride, using pyridine or other acid acceptor to neutralize the HCl evolved. Less suitably, the aminobenzothiophene reactant can be reacted with chloroacetic acid, using benzene or toluene to remove water of condensation by azeotropic distillation.

3,495,967 Patented Feb. 17, 1970 wherein R, X, Y, and Z are as aforedefined and may be on any separate 2-7 positions of the ring. The aminobenzothiophenes can be prepared by various methods known in the art, such as by reduction of the corresponding nitro compound. Typical methods for preparing aminobenzothiophenes and hydroxybenzothiophenes are described by Fries et al., Ann. 527, 83-114 (1937). The aminobenzothiophenes can also be prepared by the wellknown reverse Bucherer reaction from the hydroxybenzothiophenes. The N-substituted (alkyl, cycloalkyl, and alkenyl) derivatives of the aminobenzothiophenes can be prepared by any of the known alkylation and alkenylation methods. The l-oxides and 1,1-dioxides can be prepared by reacting the aminobenzothiophene reactant with hydrogen peroxide. It is preferred, however, to convert to the l-oxide, or 1,1-dioxide after preparation of the chloroacetamide. Non-limiting examples of the aminobenzothiophene reactant are:

3-phenyl-6-aminobenzothiophene B-phenyl 6-amino-7-bromobenzothiophene 4-iodo-S-aminobenZothiophene 3-nitro-4-bromo-aminobenzothiophene S-aminobenzothiophene 2-carboxy-5-aminobenz0thiophene 4-aminobenzothiophene 3-aminobenzothiophene 7 -aminobenzothiophene 4-amino-6-methylbenzothiophene 3 -amino-7-isoproxybenzothiophene 4-amino-2-ethylbenzothiophene 4-amino-7-methylthiobenzothiophene 4-amino-S-allylbenzothiophene 4-amino-7-cyclopropylbenzothiophene 2-cyano-4-aminobenzothiophene 7-thiocyano-4-aminobenzothiophene/ 2-chloro-4-aminobenzothiophene 2, 3-dichloro-4-aminobenzothiophene 1, 1 -dioxy-4-aminobenzothiophene 1-oxy-3-aminobenzothiophene N-methyl-4-aminobenzothiophene N-methyl-Z-carboxy-S-aminobenzothiophene N-isopropyl-4-aminobenZothiophene N-isopropyl-S-aminobenzothiophene N-isopropyl-7-aminobenzothiophene N-isopropyl-3-nitro-4-bromo-S-aminobenzothiophene N-vinyl-2-ethy1-4-aminobenzothiophene I N-vinyl-7-methylthio-4-aminobenzothiophene N-cyclopropyl-5-allyl-4-aminobenzothiophene N-cyclopropyl-4-aminobenzothiophene N-butenyl-4-aminobenzothiophene N-buteny1-7-cyclopropyl-4-aminobenzothiophene The following are typical of the compounds of this invention:

N'- 3-pheny1-6-benzothienyl) -chloroacetamide N- 3-phenyl-7-bromo-6-benzothienyl) -chloroacetamide N- 4-iodo-5-benzothienyl -chloroacetamide N- 3-nitro-4-bromo-S-benzothienyl) -chloroacetamide N- S-benzothienyl) -chloroacetamide N- 2-carboxy-S-benzothienyl -chloroacetamide N- (4-benzothienyl) -chloroacetamide N- Z-benzothienyl -chloroacetamide N- 3 -benzothienyl -chloroacetamide N- (7-benzothienyl) -chloroacetamide N- 6-methy1-4-benzothienyl) -chloroacetamide N-( 7-isopropoxy-3 -benzothienyl -chloroaceta-mide N- 2-ethyl-4-benzothienyl) -chloroacetamide -N- T-methylthio-4-benzothienyl) ch1oro acetamide N- -allyl-4-benzothienyl -chloroacetamide N- 7-cyclopropyl-4-benzothienyl) -chloroacetamide N- 2-cyano-4-benzothienyl) -chloroacetamide N- 7-thiocyano-4-benzothienyl) -chloroacetamide N- 2-chloro-4-benzothienyl -chloroacetamide N (2,3 -dichloro-4-benzothienyl) -chloroacetamide N-( l, l-dioxy-4-benzothienyl -chloroacetamide N-( 1-oxy-3 -benzothienyl -chloroacetamide N-methyl-N- (4ben zothienyl) -chlo roacetamide N-methyl-N-(2-carboxy-5-benzothienyl) -chloroacetamide N-isopropyl-N- (4-benzothienyl) -chloroacetamide N-isopropyl-N- S-benzothienyl -chloroacetamide N-isopropyl-N- Z-benzo thienyl) -chloro acetamide N-isopropyl-N- 7-benzothienyl -chloroacetamide N-iso pro pyl-N- (3 -nitro-4-bromo-5-b enzothienyl chloroacetamide N-vinyl-N- (2-e-thyl-4-benzothienyl -chloroacetamide N-vinyl-N- (7-methylthio-4-benzothienyl) -chloro acetamide N- cyclopropyl-N- 5-allyl-4-benzothienyl) -chl0ro acetamide N-cyclopropyl-N- (4-benzo thienyl -chloro acetamide N-butenyl-N- 4-benzothienyl) -chloroacetamide N-butenyl-N- 7-cyclopropyl-4-benzothienyl) -chloroacetamide Example N-isopropyl-4-aminobenzothiophene (B.P. 114 C./0.5 mm.) was prepared by alkylating 4-aminobenzothiophene with propylene. A mixture of 5.0 g. (0.026 mole) of N- isopropyl-4-aminobenzothiophene and 8.9 g. (0.052 mole) of chloroacetic acid anhydride was warmed for 2 hours. The mixture was then cooled and poured onto 50 g. of ice. The brown solid that separated was filtered OE and recrysstallized from 1:1 ethanol-water. A white solid was ob tained weighing 5.2 g. (74.7% yield) and melting at 1065-108" C. Infrared and nuclear magnetic resonance data support the structure for N-isopropyl-N-(4-benzothienyl chloroacetamide.

The compounds of this invention can be applied in various ways to achieve herbicidal action. They can be applied, per se, as solids or in vaporized form, but are preferably applied as the toxic components in pesticidal compositions of the compound and a carrier. The compositions can be applied, as dusts; as liquid sprays, or as gaspropelled sprays and can contain, in addition to a carrier, additives such as emulsifying agents, binding agents, gases compressed to the liquid state, odorants, stabilizers, and the like. A wide variety of liquid and solid carriers can be used. Non-limiting examples of solid carriers include talc, bentonite, diatomaceous earth, pyrophyllite, fullers earth, gypsum, flours derived from cottonseeds and nut shells, and various natural and synthetic clays having a pH not exceeding about 9.5. Non-limiting examples of liquid carriers, include water; organic solvents such as alcohols, ketones, amides and esters; mineral oils such as kerosene, light oils, and medium oils; and vegetable oils such as cottonseed oil.

In practice, herbicidal application is measured in terms of pounds of herbicide applied per acre. The compounds of this invention are eifective herbicides when applied in herbicidal amounts, i.e., at rates between about 0.2 pound and about 10 pounds per acre.

Herbicidal effectiveness Method of propagating test species:

to the diameter of the seed. All other species are surface seeded and sprinkled with screened soil in an amount sufiicient to cover the seed. Immediately after planting, all pots are watered by sub-irrigation in greenhouse trays. Pots for the pre-emergence phase are seeded one day before treatment.

Planting dates for the post-emergence phase are varied so that all seedlings will reach the desired stage of development simultaneously. The proper stage of seedling development for treatment in the post-emergence phase is as follows:

Grasses.--2" in height.

Pigweed and turnips-1 or 2 true leaves visible above cotyledons.

Cotton-First true leaf 1" in length; expanded cotyledons.

Corn.-3"4" in height.

Beans.--Primary leaves expanded, growing point at primary leaf node.

Method of treatment Spray applications are made in a hood containing a movable belt and fixed spray nozzle. For passage through the spray hood, one pot of each species (pro-emergence phase) is placed on the forward half of a wooden flat and one pot of established plants (post-emergence phase) is placed on the rear half of the flat. Treatments are moved to the greenhouse after spraying. Watering during the observation period is applied only by sub-irrigation.

Compounds are screened at a rate of application equivalent to 8 lbs. per acre. Two weeks after treatment the percent preand post-emergent injury is visually rated. Herbicidal testing of N-isopropyl-N-(4-benzothieny1) chloroacetamide showed the following results:

Percent Injury Pre-emergent Post-emergent Plant:

Crabgrass 90 40 Yellow foxtall- 90 50 Johnson grass 60 30 90 60 20 50 60 30 80 0 20 0 40 6 amount of an N-benzothienyl-2-chlor0acetarnide having References Cited the fmmula UNITED STATES PATENTS 2,634,201 4/1953 Mowry et a1 71-90 R 0 2,645,572 7/1953 Blicke 71-9o I 11 Cl 5 2,723,190 11/1955 Schlesinger 71-91 43052 2,723,191 11/1955 Schlesinger 71-91 X 3,268,324 8/1966 Hamm et a1. 71 11s FOREIGN PATENTS 622,131 12/1962 Belgium.

wherein R and X are selected from hydrogen, alkyl LEWIS GOTTS, Primary Examiner (C -C and alkenyl (C -C and in Which X may be on any 2 3, 5, 6, or 7 position of the ring CATHERINE L. MILLS, Assistant Examlner 2. A method of claim 1, wherein said N-benzothienyl- 15 U S Cl X R 2-chloroacetan1ide is N-isopropyl-N-(4-benzothienyl)-2- chloroacetamide. 71-91; 260330.5

237 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Ph -$5,9 7 Dated February 17, 1970 Inventor) PATRICK R. DRISCOLL and HAROLD A. KAUFMAN It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

fi Column 2, Line 1, "aminobenzthiophene" should be -a.minobenzothiophene Column 2, Line 33, "3-nitro t-bromo-,aminobenzothiophene" should be --3-nitro- -bromo5-a,minobenzothiophene-- SIGNED RND SEALED JUL14B70 Atteat:

Edwari M- F mam-nu 2. sum, m. Awaiting Officer Oomisaioner at Patents 

